<template>
  <transition
    name="el-zoom-in-top"
    @after-enter="handleEnter"
    @after-leave="handleLeave"
  >
    <div
      v-show="visible"
      class="el-picker-panel el-date-picker el-popper"
      :class="[
        {
          'has-sidebar': $slots.sidebar || shortcuts,
          'has-time': showTime
        },
        popperClass
      ]"
    >
      <div class="el-picker-panel__body-wrapper">
        <slot name="sidebar" class="el-picker-panel__sidebar"></slot>
        <div class="el-picker-panel__sidebar" v-if="shortcuts">
          <button
            type="button"
            class="el-picker-panel__shortcut"
            v-for="(shortcut, key) in shortcuts"
            :key="key"
            @click="handleShortcutClick(shortcut)"
          >
            {{ shortcut.text }}
          </button>
        </div>
        <div class="el-picker-panel__body">
          <div class="el-date-picker__time-header" v-if="showTime">
            <span class="el-date-picker__editor-wrap">
              <el-input
                :placeholder="t('el.datepicker.selectDate')"
                :value="visibleDate"
                size="small"
                @input="(val) => (userInputDate = val)"
                @change="handleVisibleDateChange"
              />
            </span>
            <span
              class="el-date-picker__editor-wrap"
              v-clickoutside="handleTimePickClose"
            >
              <el-input
                ref="input"
                @focus="timePickerVisible = true"
                :placeholder="t('el.datepicker.selectTime')"
                :value="visibleTime"
                size="small"
                @input="(val) => (userInputTime = val)"
                @change="handleVisibleTimeChange"
              />
              <time-picker
                ref="timepicker"
                :time-arrow-control="arrowControl"
                @pick="handleTimePick"
                :visible="timePickerVisible"
                @mounted="proxyTimePickerDataProperties"
              >
              </time-picker>
            </span>
          </div>
          <div
            class="el-date-picker__header"
            :class="{
              'el-date-picker__header--bordered':
                currentView === 'year' || currentView === 'month'
            }"
            v-show="currentView !== 'time'"
          >
            <button
              type="button"
              @click="prevYear"
              :aria-label="t(`el.datepicker.prevYear`)"
              class="el-picker-panel__icon-btn el-date-picker__prev-btn el-icon-d-arrow-left"
            ></button>
            <button
              type="button"
              @click="prevMonth"
              v-show="currentView === 'date'"
              :aria-label="t(`el.datepicker.prevMonth`)"
              class="el-picker-panel__icon-btn el-date-picker__prev-btn el-icon-arrow-left"
            ></button>
            <span
              @click="showYearPicker"
              role="button"
              class="el-date-picker__header-label"
              >{{ yearLabel }}</span
            >
            <span
              @click="showMonthPicker"
              v-show="currentView === 'date'"
              role="button"
              class="el-date-picker__header-label"
              :class="{ active: currentView === 'month' }"
              >{{ t(`el.datepicker.month${month + 1}`) }}</span
            >
            <button
              type="button"
              @click="nextYear"
              :aria-label="t(`el.datepicker.nextYear`)"
              class="el-picker-panel__icon-btn el-date-picker__next-btn el-icon-d-arrow-right"
            ></button>
            <button
              type="button"
              @click="nextMonth"
              v-show="currentView === 'date'"
              :aria-label="t(`el.datepicker.nextMonth`)"
              class="el-picker-panel__icon-btn el-date-picker__next-btn el-icon-arrow-right"
            ></button>
          </div>

          <div class="el-picker-panel__content">
            <date-table
              v-show="currentView === 'date'"
              @pick="handleDatePick"
              :selection-mode="selectionMode"
              :first-day-of-week="firstDayOfWeek"
              :value="value"
              :default-value="defaultValue ? new Date(defaultValue) : null"
              :date="date"
              :cell-class-name="cellClassName"
              :disabled-date="disabledDate"
            >
            </date-table>
            <year-table
              v-show="currentView === 'year'"
              @pick="handleYearPick"
              :value="value"
              :default-value="defaultValue ? new Date(defaultValue) : null"
              :date="date"
              :disabled-date="disabledDate"
            >
            </year-table>
            <month-table
              v-show="currentView === 'month'"
              @pick="handleMonthPick"
              :value="value"
              :default-value="defaultValue ? new Date(defaultValue) : null"
              :date="date"
              :disabled-date="disabledDate"
            >
            </month-table>
          </div>
        </div>
      </div>

      <div
        class="el-picker-panel__footer"
        v-show="footerVisible && currentView === 'date'"
      >
        <el-button
          size="mini"
          type="text"
          class="el-picker-panel__link-btn"
          @click="changeToNow"
          v-show="selectionMode !== 'dates'"
        >
          {{ t('el.datepicker.now') }}
        </el-button>
        <el-button
          plain
          size="mini"
          class="el-picker-panel__link-btn"
          @click="confirm"
        >
          {{ t('el.datepicker.confirm') }}
        </el-button>
      </div>
    </div>
  </transition>
</template>

<script type="text/babel">
import {
  formatDate,
  parseDate,
  getWeekNumber,
  isDate,
  modifyDate,
  modifyTime,
  modifyWithTimeString,
  clearMilliseconds,
  clearTime,
  prevYear,
  nextYear,
  prevMonth,
  nextMonth,
  changeYearMonthAndClampDate,
  extractDateFormat,
  extractTimeFormat,
  timeWithinRange
} from '../../../../src/utils/date-util'
import Clickoutside from '../../../../src/directives/clickoutside'
import Locale from '../../../../src/mixins/locale'
import { ElInput } from '../../../../src/components/Input'
import { ElButton } from '../../../../src/components/Button'
import TimePicker from './time'
import YearTable from '../basic/year-table'
import MonthTable from '../basic/month-table'
import DateTable from '../basic/date-table'
import { useDateEmitter } from '../../index'

export default {
  mixins: [Locale],
  directives: { Clickoutside },

  watch: {
    showTime(val) {
      /* istanbul ignore if */
      if (!val) return
      this.$nextTick(() => {
        const inputElm = this.$refs.input.$el
        if (inputElm) {
          this.pickerWidth = inputElm.getBoundingClientRect().width + 10
        }
      })
    },

    value(val) {
      if (this.selectionMode === 'dates' && this.value) return
      if (isDate(val)) {
        this.date = new Date(val)
      } else {
        this.date = this.getDefaultValue()
      }
    },

    defaultValue(val) {
      if (!isDate(this.value)) {
        this.date = val ? new Date(val) : new Date()
      }
    },

    timePickerVisible(val) {
      if (val) this.$nextTick(() => this.$refs.timepicker.adjustSpinners())
    },

    selectionMode(newVal) {
      if (newVal === 'month') {
        /* istanbul ignore next */
        if (this.currentView !== 'year' || this.currentView !== 'month') {
          this.currentView = 'month'
        }
      } else if (newVal === 'dates') {
        this.currentView = 'date'
      }
    }
  },

  methods: {
    proxyTimePickerDataProperties() {
      const format = (timeFormat) => {
        this.$refs.timepicker.format = timeFormat
      }
      const value = (value) => {
        this.$refs.timepicker.value = value
      }
      const date = (date) => {
        this.$refs.timepicker.date = date
      }
      const selectableRange = (selectableRange) => {
        this.$refs.timepicker.selectableRange = selectableRange
      }

      this.$watch('value', value)
      this.$watch('date', date)
      this.$watch('selectableRange', selectableRange)

      format(this.timeFormat)
      value(this.value)
      date(this.date)
      selectableRange(this.selectableRange)
    },

    handleClear() {
      this.date = this.getDefaultValue()
      this.trigger('pick', null)
    },

    emit(value, ...args) {
      if (!value) {
        this.trigger('pick', value, ...args)
      } else if (Array.isArray(value)) {
        const dates = value.map((date) =>
          this.showTime ? clearMilliseconds(date) : clearTime(date)
        )
        this.trigger('pick', dates, ...args)
      } else {
        this.trigger(
          'pick',
          this.showTime ? clearMilliseconds(value) : clearTime(value),
          ...args
        )
      }
      this.userInputDate = null
      this.userInputTime = null
    },

    // resetDate() {
    //   this.date = new Date(this.date);
    // },

    showMonthPicker() {
      this.currentView = 'month'
    },

    showYearPicker() {
      this.currentView = 'year'
    },

    // XXX: 没用到
    // handleLabelClick() {
    //   if (this.currentView === 'date') {
    //     this.showMonthPicker();
    //   } else if (this.currentView === 'month') {
    //     this.showYearPicker();
    //   }
    // },

    prevMonth() {
      this.date = prevMonth(this.date)
    },

    nextMonth() {
      this.date = nextMonth(this.date)
    },

    prevYear() {
      if (this.currentView === 'year') {
        this.date = prevYear(this.date, 10)
      } else {
        this.date = prevYear(this.date)
      }
    },

    nextYear() {
      if (this.currentView === 'year') {
        this.date = nextYear(this.date, 10)
      } else {
        this.date = nextYear(this.date)
      }
    },

    handleShortcutClick(shortcut) {
      if (shortcut.onClick) {
        shortcut.onClick(this)
      }
    },

    handleTimePick(value, visible, first) {
      if (isDate(value)) {
        const newDate = this.value
          ? modifyTime(
              this.value,
              value.getHours(),
              value.getMinutes(),
              value.getSeconds()
            )
          : modifyWithTimeString(this.getDefaultValue(), this.defaultTime)
        this.date = newDate
        this.emit(this.date, true)
      } else {
        this.emit(value, true)
      }
      if (!first) {
        this.timePickerVisible = visible
      }
    },

    handleTimePickClose() {
      this.timePickerVisible = false
    },

    handleMonthPick(month) {
      if (this.selectionMode === 'month') {
        this.date = modifyDate(this.date, this.year, month, 1)
        this.emit(this.date)
      } else {
        this.date = changeYearMonthAndClampDate(this.date, this.year, month)
        // TODO: should emit intermediate value ??
        // this.emit(this.date);
        this.currentView = 'date'
      }
    },

    handleDatePick(value) {
      if (this.selectionMode === 'day') {
        let newDate = this.value
          ? modifyDate(
              this.value,
              value.getFullYear(),
              value.getMonth(),
              value.getDate()
            )
          : modifyWithTimeString(value, this.defaultTime)
        // change default time while out of selectableRange
        if (!this.checkDateWithinRange(newDate)) {
          newDate = modifyDate(
            this.selectableRange[0][0],
            value.getFullYear(),
            value.getMonth(),
            value.getDate()
          )
        }
        this.date = newDate
        this.emit(this.date, this.showTime)
      } else if (this.selectionMode === 'week') {
        this.emit(value.date)
      } else if (this.selectionMode === 'dates') {
        this.emit(value, true) // set false to keep panel open
      }
    },

    handleYearPick(year) {
      if (this.selectionMode === 'year') {
        this.date = modifyDate(this.date, year, 0, 1)
        this.emit(this.date)
      } else {
        this.date = changeYearMonthAndClampDate(this.date, year, this.month)
        // TODO: should emit intermediate value ??
        // this.emit(this.date, true);
        this.currentView = 'month'
      }
    },

    changeToNow() {
      // NOTE: not a permanent solution
      //       consider disable "now" button in the future
      if (
        (!this.disabledDate || !this.disabledDate(new Date())) &&
        this.checkDateWithinRange(new Date())
      ) {
        this.date = new Date()
        this.emit(this.date)
      }
    },

    confirm() {
      if (this.selectionMode === 'dates') {
        this.emit(this.value)
      } else {
        // value were emitted in handle{Date,Time}Pick, nothing to update here
        // deal with the scenario where: user opens the picker, then confirm without doing anything
        const value = this.value
          ? this.value
          : modifyWithTimeString(this.getDefaultValue(), this.defaultTime)
        this.date = new Date(value) // refresh date
        this.emit(value)
      }
    },

    resetView() {
      if (this.selectionMode === 'month') {
        this.currentView = 'month'
      } else if (this.selectionMode === 'year') {
        this.currentView = 'year'
      } else {
        this.currentView = 'date'
      }
    },

    handleEnter() {
      document.body.addEventListener('keydown', this.handleKeydown)
    },

    handleLeave() {
      this.trigger('dodestroy')
      document.body.removeEventListener('keydown', this.handleKeydown)
    },

    handleKeydown(event) {
      const keyCode = event.keyCode
      const list = [38, 40, 37, 39]
      if (this.visible && !this.timePickerVisible) {
        if (list.indexOf(keyCode) !== -1) {
          this.handleKeyControl(keyCode)
          event.stopPropagation()
          event.preventDefault()
        }
        if (
          keyCode === 13 &&
          this.userInputDate === null &&
          this.userInputTime === null
        ) {
          // Enter
          this.emit(this.date, false)
        }
      }
    },

    handleKeyControl(keyCode) {
      const mapping = {
        year: {
          38: -4,
          40: 4,
          37: -1,
          39: 1,
          offset: (date, step) => date.setFullYear(date.getFullYear() + step)
        },
        month: {
          38: -4,
          40: 4,
          37: -1,
          39: 1,
          offset: (date, step) => date.setMonth(date.getMonth() + step)
        },
        week: {
          38: -1,
          40: 1,
          37: -1,
          39: 1,
          offset: (date, step) => date.setDate(date.getDate() + step * 7)
        },
        day: {
          38: -7,
          40: 7,
          37: -1,
          39: 1,
          offset: (date, step) => date.setDate(date.getDate() + step)
        }
      }
      const mode = this.selectionMode
      const year = 3.1536e10
      const now = this.date.getTime()
      const newDate = new Date(this.date.getTime())
      while (Math.abs(now - newDate.getTime()) <= year) {
        const map = mapping[mode]
        map.offset(newDate, map[keyCode])
        if (
          typeof this.disabledDate === 'function' &&
          this.disabledDate(newDate)
        ) {
          continue
        }
        this.date = newDate
        this.trigger('pick', newDate, true)
        break
      }
    },

    handleVisibleTimeChange(value) {
      const time = parseDate(value, this.timeFormat)
      if (time && this.checkDateWithinRange(time)) {
        this.date = modifyDate(time, this.year, this.month, this.monthDate)
        this.userInputTime = null
        this.$refs.timepicker.value = this.date
        this.timePickerVisible = false
        this.emit(this.date, true)
      }
    },

    handleVisibleDateChange(value) {
      const date = parseDate(value, this.dateFormat)
      if (date) {
        if (
          typeof this.disabledDate === 'function' &&
          this.disabledDate(date)
        ) {
          return
        }
        this.date = modifyTime(
          date,
          this.date.getHours(),
          this.date.getMinutes(),
          this.date.getSeconds()
        )
        this.userInputDate = null
        this.resetView()
        this.emit(this.date, true)
      }
    },

    isValidValue(value) {
      return (
        value &&
        !isNaN(value) &&
        (typeof this.disabledDate === 'function'
          ? !this.disabledDate(value)
          : true) &&
        this.checkDateWithinRange(value)
      )
    },

    getDefaultValue() {
      // if default-value is set, return it
      // otherwise, return now (the moment this method gets called)
      return this.defaultValue ? new Date(this.defaultValue) : new Date()
    },

    checkDateWithinRange(date) {
      return this.selectableRange.length > 0
        ? timeWithinRange(date, this.selectableRange, this.format || 'HH:mm:ss')
        : true
    }
  },

  components: {
    TimePicker,
    YearTable,
    MonthTable,
    DateTable,
    ElInput,
    ElButton
  },

  data() {
    return {
      popperClass: '',
      date: new Date(),
      value: '',
      defaultValue: null, // use getDefaultValue() for time computation
      defaultTime: null,
      showTime: false,
      selectionMode: 'day',
      shortcuts: '',
      visible: false,
      currentView: 'date',
      disabledDate: '',
      cellClassName: '',
      selectableRange: [],
      firstDayOfWeek: 7,
      showWeekNumber: false,
      timePickerVisible: false,
      format: '',
      arrowControl: false,
      userInputDate: null,
      userInputTime: null
    }
  },

  computed: {
    year() {
      return this.date.getFullYear()
    },

    month() {
      return this.date.getMonth()
    },

    week() {
      return getWeekNumber(this.date)
    },

    monthDate() {
      return this.date.getDate()
    },

    footerVisible() {
      return this.showTime || this.selectionMode === 'dates'
    },

    visibleTime() {
      if (this.userInputTime !== null) {
        return this.userInputTime
      } else {
        return formatDate(this.value || this.defaultValue, this.timeFormat)
      }
    },

    visibleDate() {
      if (this.userInputDate !== null) {
        return this.userInputDate
      } else {
        return formatDate(this.value || this.defaultValue, this.dateFormat)
      }
    },

    yearLabel() {
      const yearTranslation = this.t('el.datepicker.year')
      if (this.currentView === 'year') {
        const startYear = Math.floor(this.year / 10) * 10
        if (yearTranslation) {
          return (
            startYear +
            ' ' +
            yearTranslation +
            ' - ' +
            (startYear + 9) +
            ' ' +
            yearTranslation
          )
        }
        return startYear + ' - ' + (startYear + 9)
      }
      return this.year + ' ' + yearTranslation
    },

    timeFormat() {
      if (this.format) {
        return extractTimeFormat(this.format)
      } else {
        return 'HH:mm:ss'
      }
    },

    dateFormat() {
      if (this.format) {
        return extractDateFormat(this.format)
      } else {
        return 'yyyy-MM-dd'
      }
    }
  },
  setup() {
    const { trigger, on } = useDateEmitter()
    return { trigger, on }
  }
}
</script>
